cp/mv and extended attributes preservation

Hello
Currently, our cp(1) will never preserve extended attributes, and mv(1)
will only do so across the same filesystem (that is, when it can use
rename(2)). While I found no specification that it should be done, it
seems Linux and Darwin do that.
Any objection to modify cp(1) and mv(1) to preserve extended attributes?
--
Emmanuel Dreyfus
manu%netbsd.org@localhost